I take 2 TBSP in the morning, and 2 in the evening. I just put it in a mug and mix it with a small amount of water. If you don't mix it more or less immediately, it will form a semi-solid mass on the bottom of the mug and be a lot harder to mix.

I usually do it once or or twice a day. Timing is usually in the morning, upon waking or near bedtime. Dosage is from 2 to 4 tablespoons at each time, depending on how whimsy I am at the moment, mixed in some water. But then, I've been taking it for the better part of 4 months (and trying to eliminate cut down on things that could be wrecking havoc with my guts as well).

The primer link that was posted, is a pretty good resource and one should definitely ease into the whole RS/PS thing.

2) The SCFA from the gut digestion of the RS stabilizes blood glucose through the night.

All I know for sure is it really works for me. Sleep has become binary. I go to sleep and I wake up when the sun comes up or the alarm goes off. Very little waking in the night. Good dreams and feel very well rested in the morning.